Polymer containing substituted triphenylamine units

ABSTRACT

A method for making a polymer containing a first repeat unit having formula: —Ar—N(R)—Ar—(N(R′)—Ar) x — which may be substituted or unsubstituted where x is 0 or 1; each Ar is the same or different and independently is a substituted or unsubstituted aryl or heteroaryl group and R and R′ each is hydrogen or a substituent group and a second repeat unit that is the same or different from the first repeat unit and comprises a substituted or unsubstituted, aryl or heteroaryl group. The polymer is made by Suzuki polymerisation wherein the monomer from which repeat unit ( 1 ) is derived comprises one or two reactive boron groups.

[0001] The present invention relates to polymers and to a method formaking the same. The present invention particularly relates tohomopolymers, copolymers and higher order polymers obtained by themethod, particularly polymers that can be used in optical devices suchas electroluminescent devices.

[0002] Electroluminescent devices that employ an organic material forlight emission are described in PCT/WO90/13148 and U.S. Pat. No.4,539,507. The basic structure of these devices is a light-emissiveorganic layer, for instance a film of poly(p-phenylene vinylene)sandwiched between two electrodes. One of the electrodes: (the cathode)injects negative charge carriers (electrons) and the other electrode(the anode) injects positive charge carriers (holes) into thelight-emissive organic layer. The electrons and holes combine in theorganic layer to generate photons. In PCT/WO90/13148 the organiclight-emissive layer is made from an organic light-emissive materialthat is a polymer.

[0003] It is known, to use a semiconductive conjugated copolymer as thelight-emissive layer in an electroluminescent device. The semiconductiveconjugated copolymer comprises at least two chemically differentmonomeric residues which, when existing in their individual homopolymerforms, typically have different semiconductor bandgaps. The proportionof the chemically different monomeric residues in the copolymer can beselected to control the semiconductive bandgap of the copolymer so as tocontrol the optical properties of the copolymer as disclosed inPCT/GB91/01420.

[0004] For organic semiconductors, important characteristics are thebinding energies measured with respect to the vacuum level of theelectronic energy levels, particularly “the highest occupied molecularorbital” (HOMO) and “lowest unoccupied molecular orbital” (LUMO) levels.The oxidation potential and reduction potential of different polymers isgoverned by the relative HOMO and LUMO levels of the polymer. Thus, theHOMO and LUMO levels can be estimated from measurement of photoemissionand particularly measurements of the electrochemical potentials foroxidation and reduction. It is well understood in the field that suchenergies are affected by a number of factors. Accordingly, the use ofsuch values is indicative rather than quantitative.

[0005] One route to conjugated polymers is known from DE 3610649 whichdiscloses the preparation of triphenylamine homopolymers by Ullmancoupling of dibromotriphenylamine monomers with copper. An alternativeto the Ullman method is the use pf certain nickel complexes as describedin ‘Macromolecules’, 31, 1099-1103 (1998). The polymerisation reactioninvolves nickel-mediated coupling of dibromide monomers. This method isknown as ‘Yamamoto Polymerisation’. The use of the nickel catalyst inYamamoto Polymerisation presents an economic problem in terms of largescale manufacturing since this catalyst is expensive.

[0006] A further route to conjugated polymers is based on thePd-catalysed cross-coupling reaction (commonly known as the “Suzukireaction”) between an aromatic boronic acid derivative and an aromatichalide. This was reported by Suzuki in Synthetic Communications, Vol. 11No. 7 page 513 (1981). The reaction also requires a base; aqueousalkaline carbonate or bicarbonate being the most preferred. Developmentsto the “Suzuki reaction” have been the subject of U.S. Pat. No.5,777,070 and WO 00/53656, the contents of both of which areincorporated herein by reference.

[0007] Polymers preparable by the “Suzuki reaction” are described in WO99/54385; WO 00/46321 and PCT/GB00/00911. Each of these documentsdiscloses a polymer having a triarylamine repeat unit.

[0008] Japanese Patent No. 2000352824 discloses the compound:

[0009] bearing an addition polymerisable ethylenic unsaturated bond. Thecompound is photopolymerisable and is disclosed to be useful for use asa component of a lithographic printing plate. There is no mention of anoptical device, nor is there any mention of the “Suzuki reaction”.

[0010] J. Electroanal. Chem. 2000, 482(2), (211-216) discloses thefollowing compound:

[0011] as part of an investigation into boronic ester-substitutedtriphenylamines as new Lewis base-sensitive redox receptors.

[0012] The incorporation of this compound into a polymer is notdisclosed.

[0013] The present inventors have identified that there exists adeficiency in methods for making regular alternating copolymers by the“Suzuki reaction” in the prior art. The preparation of regularalternating copolymers or higher order polymers is highly advantageousfor certain polymers because a regular alternating copolymer or higherorder polymer has more defined properties as compared with thecorresponding random copolymer. For example, the emission spectrum of arandom copolymer may be spread over a broader range (i.e. it will beless defined) as compared with the corresponding regular alternatingcopolymer. Without wishing to be bound by theory it is thought thatperhaps this is due in part to conjugation between the two monomericresidues in the random copolymer.

[0014] The deficiency identified by the present inventors relates to thevery nature of the “Suzuki reaction”. It can be seen that in order toobtain a regular alternating AB copolymer from an A-containing monomerand a B-containing monomer it would be necessary to provide, forexample, a diester A-containing monomer and a dihalide B-containingmonomer or vice versa. A deficiency will exist where both A-containingmonomers and B-containing monomers only are available as, for example,dihalides because this would mean that a regular alternating ABcopolymer would not be preparable by the ‘Suzuki reaction’ and perhapswould not be preparable at all.

[0015] Similarly, the present inventors have identified that thereexists a deficiency in methods for making homopolymers by the ‘Suzukireaction’ in the prior art. The preparation of homopolymers by the‘Suzuki reaction’ is advantageous in at least partially overcoming theproblems associated with previously known methods as discussed above.Again, the deficiency identified by the present inventors relates to thevery nature of the “Suzuki reaction”. It can be seen that in order toobtain a homopolymer (A)_(n) by the ‘Suzuki reaction’ it would benecessary to provide both diester and dihalide A-containing monomers. Adeficiency would exist where A-containing monomers only are availableas, for example, dihalides because this would mean that a homopolymer(A)_(n) would not be preparable by the ‘Suzuki’ reaction.

[0016] Having identified these deficiencies in the prior art, thepresent inventors aim to at least partially overcome these deficienciesby providing hitherto unknown regular alternating copolymers obtainableby a hitherto unknown route in the ‘Suzuki reaction’. The presentinvention further aims to provide homopolymers, other copolymers andhigher order polymers obtained by the hitherto unknown route in the‘Suzuki reaction’ or a variation thereof.

[0017] Accordingly, a first aspect of the present invention provides amethod for making a linear polymer containing a first repeat unit havingformula (1):

Ar—N(R)—ArN(R′)—Ar_(x)  (1)

[0018] which may be substituted or unsubstituted where x is 0 or 1; eachAr is the same or different and independently is a substituted orunsubstituted aryl or heteroaryl group and R and R′ each is hydrogen ora substituent group and a second repeat unit that is the same ordifferent from the first repeat unit and is a substituted orunsubstituted, aryl or heteroaryl group; comprising the step ofpolymerising in a reaction mixture:

[0019] (a) a plurality of first monomers each (i) containing the firstrepeat unit and (ii) having only two reactive boron derivative groupsand a plurality of second monomers each (i) containing the second repeatunit and (ii) having at least two (preferably only two) reactive halidefunctional groups; or

[0020] (b) a plurality of first monomers each (i) containing the firstrepeat unit and (ii) having one reactive halide functional group and onereactive boron derivative group and a plurality of second monomers each(i) containing the second repeat unit and (ii) having one reactivehalide functional group and one reactive boron derivative group;

[0021] wherein the reaction mixture comprises a base and a catalyticamount of a catalyst suitable for catalysing the polymerisation of themonomers.

[0022] A second aspect of the present invention provides a linearregular alternating copolymer obtainable by the method according to oneembodiment of the first aspect of the present invention.

[0023] A third aspect of the present invention provides a monomersuitable for use in the method according to the first aspect of thepresent invention.

[0024] A fourth aspect of the present invention provides the use ofpolymer obtained by the method according to the first aspect of thepresent invention or a copolymer according to the second aspect of thepresent invention.

[0025] A fifth aspect of the present invention provides an opticaldevice or component therefor comprising a polymer obtained by the methodaccording to the first aspect of the present invention or a copolymeraccording to the second aspect of the present invention.

[0026] According to a sixth aspect of the present invention there isprovided the use of a monomer according to the third aspect of thepresent invention.

[0027] For the purposes of the present invention, the term “polymers”should be interpreted to include homopolymers, copolymers, terpolymersand higher order polymers.

[0028] For the purposes of the present invention, the phrase, “aryl andheteroaryl groups” may be taken to include substituted or unsubstitutedmononuclear and polynuclear aryl and heteroaryl groups. Polynuclear aryland heteroaryl groups may be taken to include fused ring systems as wellas ring systems joined by direct covalent bonds or via another atom suchas S, O, C or the like.

[0029] In the present method, it is preferred that the or each boronderivative group independently is selected from the group consisting ofa boronic acid group, a boronic ester group and a borane group.Furthermore, it is preferred that each reactive halide functional groupindependently is selected from the group consisting of P, Cl, Br and I.

[0030] Preferably, the reaction conditions are in accordance with eitherWO 00/53656 or U.S. Pat. No. 5,777,070. In the method of WO 00/53656,the reaction mixture comprises a catalytic amount of a catalyst suitablefor catalysing the polymerisation of the aromatic monomers (e.g.palladium) and an organic base in an amount sufficient to convert thereactive boron derivative functional groups into BX₃ ⁻ anionic groups,wherein X is independently selected from the group consisting of F, ORand OH. In U.S. Pat. No. 5,777,070 the reaction mixture contains anorganic solvent (in which the polymer forms at least a 1% solution) anaqueous solution of an inorganic base having a pKa in the range of from9 to 13, the solution having a concentration of at least 0.1N; acatalytic amount of a palladium complex and at least 0.01 mol % of aphase transfer catalyst based on the number of moles of boronic acid,boronic acid ester and borane groups in the reaction mixture.

[0031] One preferred ratio first monomer: second monomer in the reactionmixture is 1:1. However, this ratio may be varied in order to controlthe properties of the resulting polymer.

[0032] In a first embodiment of the first aspect of the presentinvention, it is preferred that the method proceeds via step (a),particularly such that each first monomer has a formula (2):

Efirst repeat unitE   (2)

[0033] where each E is a reactive boron derivative group.

[0034] In one embodiment of the method according to the first aspect ofthe present invention, each second monomer has a formula (3):

E′second repeat unitE′  (3)

[0035] where each E′ is a reactive halide functional group and thesecond repeat unit is a substituted or unsubstituted, aryl or heteroarylgroup. The resulting polymer may be as shown in general formula (4):

first repeat unit-second repeat unit_(n)   (4)

[0036] where n is at least 2.

[0037] Where the first repeat unit is different from the second repeatunit, the resulting polymer will be a regular alternating copolymer.Where the first repeat unit is the same as the second repeat unit theresulting polymer will be a homopolymer.

[0038] In a second embodiment of the first aspect of the presentinvention, it is preferred that the method proceeds via step (b) when(i) the first repeat unit is the same as the second repeat unit; and(ii) the first monomer is the same as the second monomer and has aformula (10):

E-first repeat unit-E′  (10)

[0039] The resulting polymer will be a homopolymer.

[0040] In any embodiment of the first aspect of the present invention,preferred R and R¹ groups include alkyl, alkoxy, halide (particularlyfluoro), haloalkyl (particularly CF₃), cyano, aryloxy, aryl andthioalkyl groups. A preferred first repeat unit has formula (5):

[0041] which may be substituted or unsubstituted, where x is 0 or 1 andeach Ar is the same or different from the others and independently is asubstituted or unsubstituted aryl or heteroaryl group.

[0042] Preferred Ar groups include substituted or unsubstituted phenyl,biphenyl or fluorene groups. This is because the inclusion of thesegroups can have the effect of improving hole transport properties of thefirst repeat unit. Additionally, this can have the effect of modifyingthe semiconductor bandgap of the polymer, thus, modulating thewavelength of emission obtained from the polymer when used in an opticaldevice. To this end, it is preferred that at least one of the Ar groupscomprises at substituted or unsubstituted phenyl, biphenyl or fluorenegroup. Particularly preferred first repeat units are shown by formulae(6) and (7) below:

[0043] The repeat units shown by formulas (6) and (7) may be furthersubstituted or may be unsubstituted. X′ and Y may be the same ordifferent. X, X′ and Y each independently is hydrogen or a substituentgroup. In formula (7) Ar′ is a substituted or unsubstituted aryl orheteroaryl group, or preferably is a phenyl, biphenyl or fluorene group.

[0044] X, X′ and Y may be used to improve the solubility of the polymer.In this regard, any of X, X′ and Y may be a solubilising group (i.e. anygroup which improves the solubility of the polymer as compared with theequivalent polymer not including that group). In addition, X, X′ and Ymay be used to further control the properties, particularly electronicproperties, of the polymer, particularly by controlling the HOMO andLUMO levels and, thus, the semiconductor bandgap of the polymer. Forthese purposes, electron withdrawing or electron donating groups aresuitable for use as X, X′ or Y. Particularly preferred groups includealkyl, alkoxy, carboxyalkyl, halide, cyano, aryl and heteroaryl groups.Even more preferable X, X′ and Y groups include C₁-C₁₀ alkyl and C₁-C₁₀alkoxy groups.

[0045] In one embodiment of the first aspect of the present invention,the second repeat unit may have formula (1), (5), (6) or (7) as definedabove in any general or preferred terms. In another embodiment of thefirst aspect of the present invention, the second repeat unit may beselected from the range of aryl or heteroaryl units disclosed in WO00/55927.

[0046] A polymer, particularly a regular alternating copolymer or higherorder polymer or a homopolymer, obtained by the method of the firstaspect of the present invention also is provided.

[0047] According to a second aspect of the present invention, there isprovided a linear regular alternating copolymer obtainable by the methodaccording to one embodiment of the first aspect of the presentinvention.

[0048] In some copolymers and higher order polymers, it is possible todefine different regions where each region may be defined to have adistinct HOMO level and a distinct LUMO level and thus a distinctsemiconductor bandgap. Considering a region as a monomeric residue, ithas been identified that it is possible to improve the distinctness ofthese regions where the monomeric residues are assembled in the form ofa regular alternating copolymer or higher order polymer rather than arandom copolymer or higher order polymer. Accordingly, a linear regularalternating copolymer according to the second aspect of the presentinvention will have more defined properties having regard to theindividual properties of the first and second repeat units when used ina polymer as compared with a random copolymer. Linear regularalternating copolymers according to the second aspect of the presentinvention thus are highly desirable, especially for use in an opticaldevice.

[0049] Hitherto unknown linear regular alternating copolymers that areobtainable by the method according to the first aspect of the presentinvention include those having two different triarylamine-containingrepeat units, that is to say, linear regular alternating copolymers havefirst and second repeat units that are different from each other, bothhaving a general formula as shown in or defined with reference toformulae (5), (6) or (7) above.

[0050] In this regard, a copolymer according to the second aspect of thepresent invention may be considered to be bi-functional when used in anoptical device where the first repeat unit has one function and thesecond repeat unit has another. Typically, the two functions will betransporting positive charge carriers and accepting and combiningpositive and negative charge carriers to generate light.

[0051] Such copolymers include a copolymer having formula ( 8)

[0052] where n is at least 2 and Ar′, X, X′ and Y are as defined in anyembodiment above in relation to the first aspect of the presentinvention.

[0053] In the polymer having formula (8), further substituents also maybe used to improve the solubility of the polymer and/or to furthercontrol the HOMO and LUMO levels. Any substituents may be on the groupspendent to nitrogen. This avoids the substituents being in too closeproximity to the polymerisation sites in the monomers used to preparethe polymer. However, substituents also may be provided in sites otherthan those on the groups pendent to nitrogen.

[0054] Typically, a polymer obtained by the method according to thefirst aspect of the present invention and copolymers according to thesecond aspect of the present invention will be soluble in non-polarsolvents. Typical solvents include common organic solvents, toluene,xylene, THF and organic ink-jet ink formations.

[0055] Typically, a polymer obtained by the method according to thefirst aspect of the present invention and a copolymer according to thesecond aspect of the present invention will have an average molecularweight of at least M_(n)=about 10,000 daltons. Preferably, they willhave an average molecular weight in the range 10,000 to 10⁶. Controllingthe molecular weight of the polymer is one way of controlling therheological properties of the polymer.

[0056] It is envisaged that a polymer obtained by the method accordingto the first aspect of the present invention and a copolymer accordingto the second aspect of the present invention will be useful for chargetransport, particularly for transporting positive charge carriers,and/or emitting light in a optical device.

[0057] A polymer of particular interest having general formula (8) isshown in general formula (9):

[0058] which may be further substituted or unsubstituted and where n isat least 2 and X, X′, and Y independently are selected from the groupconsisting of C₁-C₁₀ alkyl or C₁-C₁₀ alkoxy groups.

[0059] According to a third aspect of the present invention, there isprovided a monomer suitable for the preparation of a linear polymerhaving formula (11) or (12):

[0060] where E and E′ are as defined above in relation to formulas (2)and (3) respectively and x and Ar are as defined above in any general orpreferred embodiment according to the first aspect of the presentinvention.

[0061] Monomers according to the third aspect of the present inventionare suitable for use in the method according to the first aspect of thepresent invention. Generally, the monomers according to the third aspectof the present invention have opened up the way for the preparation ofhomopolyamines and regular alternating amine-containing copolymers orhigher order polymers by the ‘Suzuki reaction’. This allows good controlof the hole injection properties in the resultant polymer.

[0062] A fourth aspect of the present invention provides the use of apolymer obtained by the method according to the first aspect of thepresent invention or a copolymer according to the second aspect of thepresent invention as a component in an optical device. Preferably, thepolymer is used for transporting positive charge carriers and/or foraccepting and combining positive and negative charge carriers togenerate light in an optical devices

[0063] Due to the nature of either the first or second repeat unitdefined above, it is envisaged that when the present polymers are usedfor combining positive and negative charges carriers to generate lightin an optical device, although not so limited, they predominantly willbe useful as sources of “blue” light. For the purposes of the presentinvention, “blue” light may be defined to include light having awavelength in the range from 360 nm to 490 nm. Nevertheless, polymershaving a first repeat unit as defined above also may be useful assources of light having a wavelength outside this range.

[0064] Specifically, the optical device may comprise anelectroluminescent device.

[0065] Other uses for a polymer obtained by the method according to thefirst aspect of the present invention or a copolymer according to thesecond aspect of the present invention include use as a hole transportmaterial or use in a photovoltaic device.

[0066] Where the present polymer is soluble, this confers the advantageof allowing the polymer to be processed in solution.

[0067] A film or coating comprising a polymer obtained by the methodaccording to the first aspect of the present invention or a copolymeraccording to the second aspect of the present invention also isprovided. Further, a composition comprising a mixture or blendcomprising one or more polymers obtained by the method according to thefirst aspect of the present invention or one or more copolymersaccording to the second aspect of the present invention is provided.Preferably, the mixture or blend will comprise one or two furtherdifferent polymers.

[0068] The fifth aspect of the present invention provides an opticaldevice or a component therefor, which comprises a substrate and apolymer obtained by the method according to the first aspect of thepresent invention or a copolymer according to the second aspect of thepresent invention supported on the substrate. Preferably the opticaldevice comprises an electroluminescent device.

[0069] Hole transport materials or components and electron transportmaterials or components generally may be referred to as charge transportmaterials or components.

[0070] A preferred electroluminescent device according to the presentinvention comprises a first charge carrier injecting layer for injectingpositive charge carriers, a second charge injecting layer for injectingnegative charge carriers, a light-emissive layer for accepting andcombining positive and negative charge carriers from the first andsecond charge injecting layers to generate light and optionally one ormore charge transport layers located either between the first chargeinjecting layer and the light-emissive layer or between the secondcharge injecting layer and the light-emissive layer. The light-emissivelayer will comprise a light-emissive component and optionally one ormore positive and/or negative charge transport components. Thelight-emissive layer will comprise at least one polymer obtained by themethod according to the first aspect of the present invention or atleast one copolymer according to the second aspect of the presentinvention. A single polymer obtained by the method according to thefirst aspect of the present invention or a single copolymer according tothe second aspect of the present invention may be provided as thelight-emissive component and/or as a positive charge transportcomponent.

[0071] It will be appreciated that the light-emissive layer may beformed from a blend of materials including one or more polymers obtainedby the method according to the first aspect of the present invention orone or more copolymers according to the second aspect of the presentinvention, and optionally further different polymers. As mentionedabove, the one or more polymers obtained by the method according to thefirst aspect of the present invention or the one or more polymersaccording to the second aspect of the present invention may be includedin order to improve the efficiency of charge transport from theelectrodes to the light-emissive component, particularly to improve theefficiency of hole transport. Alternatively or additionally, a polymeraccording to the present invention (which may be the same polymerincluded to improve the efficiency of charge transport) may be includedas the light-emissive component. Where a polymer according to thepresent invention is included as at least the light-emissive component,the blend would comprise greater than 0.1%. by weight of the polymeraccording to the second aspect of the present invention, preferably fromabout 0.2 to 100, more preferably 0.5 to 50% by weight, with theremainder of the blend comprising further charge transport polymers.

[0072] Alternatively, as indicated above, a polymer obtained by themethod according to the first aspect of the present invention or acopolymer according to the second aspect of the present invention may beprovided in an electroluminescent device as a discrete layer situatedbetween either the first or second charge injecting layers and adiscrete layer comprising the light-emissive component. Also, it may beprovided as a discrete layer which is the light-emissive component.These discrete layers optionally may be in contact with one or more(additional) hole and/or electron transporting layers.

[0073] A sixth aspect of the present invention provides the use of amonomer according to the third aspect of the present invention for thepreparation of a polymer. Preferably, the use is for the preparation ofa polymer that is provided as a component of an optical device. Morepreferably, the use is for the preparation of a polymer wherein thepolymer is provided as a light-emissive component and/or a positivecharge transport component of an optical device.

[0074] The present invention now will be described in more detail withreference to the accompanying drawings in which:

[0075]FIG. 1 is a schematic diagram of an optical device.

EXAMPLE 1

[0076] Preparation of PFB Homopolymer

[0077] A solution of the pinacol diester of PFB boronic acid (5.00 g, 7mmol), dibromo-PFB (4.79 g, 7 mmol), and dichloro bis(triphenylphosphine) palladium (25 mg) in toluene (100 mL) was de-gassed withnitrogen. After 1 hour, tetraethyl ammonium hydroxide (24 mL) was, addedto the reaction mixture and the suspension heated to −120° C. (externaltemp). After 18 hours, the reaction was end-capped with bromobenzene andthe glycol ester of benzeneboronic acid. The reaction mixture was pouredinto methanol to precipitate the polymer which was then filtered anddried, affording 6.3 g of polymer (Mn 23,000).

EXAMPLE 2

[0078] Preparation of TFB-PFB Copolymer

[0079] The process of example 1 was followed except that a boronic acidester of TFB was used in place of PFB as outlined in the scheme below.

EXAMPLE 3

[0080] Optical Device

[0081] A suitable device structure is shown in FIG. 1. The anode 2 has alayer of transparent indium-tin oxide supported on a glass or plasticsubstrate 1. The anode 2 layer has a thickness between 1000 to 2000 Å,usually about 1500 Å. The cathode 5 is a Ca layer having an approximatethickness of 1500 Å. Between the electrodes is a light-emissive layer 4having a thickness up to about 1000 Å. The light-emissive layer 4comprises between 0.5 to 100% by weight of a polymer according to thepresent invention as a combined light-emissive component and holetransport component with the remainder of the light-emissive layerconsisting of hole and/or electron transport material. The polymeraccording to the present invention, for example may be a TFB-PFB regularalternating copolymer.

[0082] Advantageously, the device includes a hole transport materiallayer 3 of PEDOT having a thickness of about 1000 Å. Layer 6 is anencapsulant layer of suitable thickness.

1. A method for making a polymer containing a first repeat unit havingformula (1): Ar—N(R)—ArN(R′)—Ar_(x)  (1) which may be substituted orunsubstituted where x is 0 or 1; each Ar is the same or different andindependently is a substituted or unsubstituted aryl or heteroaryl groupand R and R′ each is hydrogen or a substituent group and a second repeatunit that is the same or different from the first repeat unit andcomprises a substituted or unsubstituted, aryl or heteroaryl group,comprising the step of polymerising in a reaction mixture: (a) aplurality of first monomers each (i) containing the first repeat unitand (ii) having only two reactive boron derivative groups and aplurality of second monomers each (i) containing the second repeat unitand (ii) having at least two reactive halide functional groups; or (b) aplurality of first monomers each (i) containing the first repeat unitand (ii) having one reactive halide functional group and one reactiveboron derivative group and a plurality of second monomers each (i)containing the second repeat unit and (ii) having one reactive halidefunctional group and one reactive boron derivative group; wherein thereaction mixture comprises a base and a catalytic amount of a catalystsuitable for catalysing the polymerisation of the monomers.
 2. A methodaccording to claim 1 (b), wherein the first repeat unit is the same asthe second repeat unit; and each first monomer is the same as the secondmonomer and has a formula (10): E-first repeat unit-E′  (10) where E² isa reactive boron derivative group that is selected from the groupconsisting of a boronic acid group a boronic ester group and a boranegroup, and E′ is a reactive halide functional group.
 3. A methodaccording to claim 1 (a) wherein each first monomer has a formula (2):Efirst repeat unitE   (2) where each E is a reactive boron derivativegroup that is selected from the group consisting of a boronic acidgroup, a boronic ester group and a borane group.
 4. A method accordingto claim 3, where each second monomer has a formula (3): E′secondrepeat unitE′  (3) where each E′ is a reactive halide functional group,such that the polymer comprises a polymer having formula (4): firstrepeat unit-second repeat unit_(n)   (4) where n is at least
 2. 5. Amethod according to claim 3 or claim 4, wherein the first repeat unit isthe same as the second repeat unit.
 6. A method according to claim 3 orclaim 4, wherein the first repeat unit is different from the secondrepeat unit.
 7. A method according to claim 1, wherein the first repeatunit has formula (5):

which may be substituted or unsubstituted, where x is 0 or 1 and each Aris the same or different.
 8. A method according to claim 7, wherein atleast one of the Ar groups comprises a substituted or unsubstitutedphenyl, biphenyl or fluorene group.
 9. A method according to claim 8,wherein the first repeat unit has formula (6):

which may be further substituted or unsubstituted and where X ishydrogen or a substituent group.
 10. A method according to claim 8,wherein the repeat unit has formula (7):

which may be further substituted or unsubstituted and where X′ and Yeach independently is hydrogen or a substituent group and Ar is aphenyl, biphenyl or fluorene group.
 11. A method according to claim 9,wherein X′ and Y are the same or different and each of X, X′ and Y isindependently selected from the group consisting of alkyl, alkoxy,carboxyalkyl, halide, cyano, aryl and heteroaryl groups.
 12. A methodaccording to claim 1, where the second repeat unit has a formula (5):


13. A polymer obtained by the method as defined in claim
 1. 14. Apolymer according to claim 23, wherein the polymer is a homopolymer or aregular alternating copolymer.
 15. A linear regular alternatingcopolymer obtainable by the method as defined in claim 4, where thesecond repeat unit is of formula (5):


16. A linear alternating copolymer according to claim 15 having aformula (8):

which may be further substituted or unsubstituted, where n is at least2, is a phenyl, biphenyl or fluorene group, X is hydrogen or asubstituent group, and X′ and Y are each independently hydrogen or asubstituent group.
 17. A linear alternating copolymer according to claim16 having a formula (9):

which may be further substituted or unsubstituted and where n is atleast 2 and X, X′, and Y independently are selected from the groupconsisting of C₁-C₁₀ alkyl. or C₁C₁₀ alkoxy groups.
 18. A linearalternating copolymer according to claim 15 having an average molecularweight in the range 10,000 to 10⁶.
 19. A monomer suitable for thepreparation of a linear polymer having formula (11) or formula (12):

where E and E′ are as defined in claim 2, and x is 0 or 1, provided thatthe following monomer is excluded:


20. A component in an optical device comprising a polymer as defined inclaim
 13. 21. A component in an optical device according to claim 20 fortransporting positive charge carriers and/or for accepting and combiningpositive and negative charge carriers to generate light in said opticaldevice.
 22. An electroluminescent device comprising an optical deviceaccording to claim
 20. 23. A film comprising a polymer as defined inclaim
 13. 24. A coating comprising a polymer as defined in claim
 13. 25.A composition comprising a mixture which comprises a polymer as definedin claim
 13. 26. A composition according to claim 23, wherein themixture comprises one or two further polymers.
 27. An optical device ora component therefor, which comprises a substrate and a polymeraccording to claim 13 supported on the substrate.
 28. An optical deviceaccording to claim 27, wherein the optical device comprises anelectroluminescent device.
 29. An optical device according to claim 28,wherein the electroluminescent device comprises: a first chargeinjecting layer for injecting positive charge carriers; a second chargeinjecting layer for injecting negative charge carriers; a light-emissivelayer located between the first and second charge injecting layerscomprising a light-emissive component for accepting and combiningpositive and negative charge carriers to generate light and optionally apositive charge transport component for transporting positive chargecarriers to the light-emissive component: wherein the light-emissivelayer comprises said polymer as the light-emissive component and/or theoptional positive charge transport component.
 30. A polymer prepared fora monomer having formula (11) or formula (12):

where E and E′ are as defined in claim 2, x is 0 or
 1. 31. An opticaldevice comprising a polymer prepared from a monomer having formula (11)or formula (12):

where E and E′ are as defined in claim
 2. 32. An optical deviceaccording to claim 31, wherein the polymer is provided as alight-emissive component and/or a positive charge transport component ofsaid optical device.
 33. A method according to claim 4, wherein thefirst repeat unit is the same as the second repeat unit.
 34. A methodaccording to claim 4, wherein the first repeat unit is different fromthe second repeat unit.
 35. A method according to claim 10, wherein X′and Y are the same or different and each of X, X′ and Y is independentlyselected from the group consisting of alkyl, alkoxy, carboxyalkyl,halide, cyano, aryl and heteroaryl groups.
 36. A method according toclaim 12, wherein at least one of the Ar groups comprises a substitutedor unsubstituted phenyl, biphenyl, or fluorene group.
 37. A methodaccording to claim 36, wherein the first repeat unit has formula (6):

which may be further substituted or unsubstituted and where X ishydrogen or a substituent group.
 38. A method according to claim 36,wherein the repeat unit has formula (7):

which may be further substituted or unsubstituted and where X′ and Yeach independently is hydrogen or a substituent group and Ar is aphenyl, biphenyl or fluorene group.
 39. A method according to claim 37,wherein X′ and Y are the same or different and each of X, X′ and Y isindependently selected from the group consisting of alkyl, alkoxy,carboxyalkyl, halide, cyano, aryl and heteroaryl groups.
 40. Monomer ofclaim 19, wherein each Ar is independently a substituted orunsubstituted phenyl, biphenyl, or fluorene group.
 41. Anelectroluminescent device comprising an optical device according toclaim 21.